Check service sheets for actual models as there are variations.
A3-A4sd 3pole(HSS217), A3 F.Scotsman (HSS220), Henry (HSS258),
A3/A4sd 5 pole (HSS256), A1 5pole (HSS259).
A1 Flying Scotsman Set & Railroad (HSS315 & HSS316, R1072, R2675